Billionaire Mike Bloomberg plans to spend at least $100 million to help Joe Biden win Florida in November's election, the Washington Post reports.

Why it matters: Taking Florida would be a knockout blow for Biden, who could then win the election outright simply by retaining all the states that Hillary Clinton won in 2016. He would not have to defeat President Trump in swing states Michigan, Pennsylvania, Wisconsin, North Carolina or Arizona, per the Post.

The big picture: Cook Political Report on Thursday shifted its prediction for Florida from "leans Democratic" to "toss up," after a number of polls showed the race tightening. Some Biden advisers have expressed concern about his soft support among Hispanic voters, who make up more than 20% of the electorate in Florida.

What they're saying: "Voting starts on Sept. 24 in Florida so the need to inject real capital in that state quickly is an urgent need,” Bloomberg adviser Kevin Sheekey told the Post. "Mike believes that by investing in Florida it will allow campaign resources and other Democratic resources to be used in other states, in particular the state of Pennsylvania."

Go deeper: Bloomberg group warns Trump will appear to win big on Election Night before mail-in ballots are counted